Superheater unit and boiler using same



Sept. 1, 1931. J. A. BARNES I 1,821,134

SUPERHEATER UNIT AND BOILER USING SAME Filed May 31, 1930 IN V EN TOR.

John ABarnes.

ATTORNEY l atented Sept. 1 1931 TATES PATENT OFFICE JOHN A. BARNES, OFCHAIEPAQUA, NEW YCB/K, ASSIGNOR 'TO THE SUPERHEATER COMPANY, OF NEWYORK, N. Y.

SUPERHEATER UNIT AND BOILER USING SAME Application filed. May 31, 1930.Serial No. 457,998.

My invention relates to superheater units and more particularly to thoseemployed in smoke tube boilers and to boilers employing such units.

Superheater units under certain conditions which occur in operation havea core of steam at lower temperature than the layer in contact with theinner surface of the unit. This condition is more apt to occur when theengine supplied by the boiler is operating under light load and resultsin supplying the engine with steam of lower temperature than thatdesired. The rapid changes of cylinder and piston temperature producedby variations of steam temperature cause undesirable stresses in theengine cylinder parts.

It is the principal object of my invention to provide a smoke fluesuperheater unit which shall maintain a more uniform steam temperaturewith varying loads than is obtained with superheater units of the typeordinarily used in smoke tube boilers.

The novel features of my invention are pointed out with particularity inthe ap pended claims. In order, however, that my invention may beclearly understood, I will now describe in detail, in connection withthe accompanying drawings, an illustrative embodiment of my invention.In the drawings,

Fig. 1 is a longitudinal sectional view taken on a vertical planethrough the rear end of a locomotive boiler in accordance with myinvention.

Fig. 2 is a fragmentary sectional view of a portion of Fig. 1illustrating the return bend portion of a superheater unit in accordancewith my invention on an enlarged scale.

Referring to the drawings more in detail, 10 indicates the shell of alocomotive boiler having a furnace chamber 12 and a tube sheet 14 at thefront of the chamber 12. Large smoke tubes 16 and ordinary smoke tubes18 have their rear ends opening into the fire box 12 through aperturesin the flue sheet 14 and are connected to the flue sheet in the usualmanner. The large tubes 16 are designed to receive superheater units 20,20, such units extending rearwardly 1n. the usual manner to pointssomewhat close to the flue sheet 14 at which points the parallel pipelengths 22, 22 of the units are 28, 28 of materially less diameter thanthe.

lengths '22 and whose open mouths lie centrally oflengths 22 in a planetransverse to the axis of pipe 22'adjacent the inner wall 30 of thereturn bend 24. The pipe lengths 28 extend in the general directionparallel to the lengths 22 and pass through apertures in the outer wall32 of the bend 24, the outer ends of the lengths28 being connected by asecond return bend 34. It will be seen, therefore,.that.as clearlyindicated by the arrowsin Fig; 1, the central core of steam in pipes 22is taken out at points near bends 24 by pipes 28 of extensions 27 inwhich the steam is further heated and returned to the large pipes of theunits at points adjacent to, but on the other sides of inner walls 30from which the steam was taken out. In order to assure tight joints atthe points where pipes 28 pass through the walls of bends 24 I prefer toweld the pipe lengths 28 to the bends by oxyacetylene or electric weldsindicated at 36, 36.

As above indicated, the smoke tubes 16 for receiving superheater unitsare reduced in diameter at their rear or intakeends forming shoulders26. In order that the extension units 27 may act with maximumefficiency, I prefer to extend them into the reduced portions 38 oftubes 16 and for this purpose bend the pipe sections 28 as indicated at39 so that the rear ends of such sections lie close together and may bereadily inserted into the reduced tube ends 38.

In the case of a boiler designed initially to use units within myinvention, the distance between the return bends 34 and the flue sheet14 will be made such that the bends 34 will not be overheated. Thetemperature a given distance forward of the flue sheet 14 depends uponthe construction of the fire box and the fuel used therein so that alocomotive boiler originally designed for the ordinary type ofsuperheater unit sometimes cannot employ a unit in accordance with myinvention on account of there being danger of over-heating the returnbend 34. In such cases, however, I have found that it is usuallypossible to install an arch of spaced water tubes 40, or other heatabsorbing surface, in the fire box 12 so that the gases must pass overit before reaching the flue sheet 14 and thereby to protect the returnbend 34 from over-heating.

I claim:

1. A superheater unit having pipe lengths connected by a return bend andpipe lengths of smaller diameter than said first pipe lengths havingmouths opening within said first lengths and extending in the samegeneral direction as said first lengths throughthe wall of said bend atthe outer side thereof, means forming a steam tight joint between saidwall and said smaller pipe lengths, and a return bend connecting saidsmaller pipe lengths outside said bend.

2. A superheater unit as set forth in claim 1 and in which the pipelengths of smaller diameter are set closer together for the portion ofthe lengths adjacent the bend connecting them.

3. The combination with a boiler having a smoke fine of reduced diameternear its inlet end, of a superheater unit in said fine and having pipelengths connected to a return bend near the portion ofthe smoke flue ofreduced diameter, said unit having relatively small and short pipelengths extending through the outer wall of said return bend and openinginto said first pipe lengths adjacent said bend, said smaller pipelengths lying close together at their forward. ends and extending intothe reduced portion of said smoke flue, and a return bend connectingsaid forward ends.

4. The combination in a heat absorbing element of a main unit comprisinga pair of parallel pipe lengths connected at one end by a return bend,an auxiliary unit adapted to withdraw the central core of steam out ofone of said lengths adjacent said bend and to return it to the other ofsaid lengths adjacent said bend.

5. The combination in a heat absorbing smaller lengths.

JOHN A. BARNES.

element of a pair of parallel pipe lengths united at one end by a returnbend and a pair of relatively small diameter pipe lengths in almementwith said lengths passing through

